1. Field of the Invention
The present invention relates to a sheet processing apparatus that performs a given process on a sheet, and to an image forming system including the sheet processing apparatus.
2. Description of the Related Art
Some of such sheet processing apparatuses are known to perform folding on a sheet on which an image is formed by an image forming apparatus. The sheet processing apparatus disclosed in Japanese Patent No. 4721463 includes a folding plate having an edge that presses a sheet surface of a sheet bundle which is a bundle of a plurality of sheets from a direction perpendicular to the sheet surface at a folding position on the sheet surface, and a folding roller pair positioned facing each other across a moving path of the folding plate, and nipping the sheet bundle. The sheet bundle is folded by causing the folding plate to push the sheet bundle into a sheet folding nip between the folding roller pair, and causing the folding roller pair to convey the sheet bundle while nipping both sides of the folding position.
On the downstream of the folding roller pair in the sheet bundle conveying direction, a fold-enhancing roller pair is also provided. To perform fold-enhancing on the folded portion of the sheet bundle, the fold-enhancing roller pair is moved in a sheet width direction, which is a direction perpendicular to the sheet bundle conveying direction, by receiving a driving force of a driving motor. The fold-enhancing roller pair includes a first roller member and a second roller member each of which has a shaft extending in the sheet bundle conveying direction, and each of which is arranged in a manner facing the other across the sheet bundle. The fold-enhancing roller pair is moved in the sheet width direction, while nipping the folded portion of the sheet bundle between the first roller member and the second roller member, to perform fold-enhancing on the folded portion.
In a configuration in which the folding plate pushes the sheet surface into the sheet folding nip and the fold-enhancing roller pair is moved in the sheet width direction along a fold of the sheet bundle, the operation areas of the folding plate and the fold-enhancing roller pair intersect with the sheet conveying path. Therefore, when any abnormality such as jamming occurs, the folding plate and the fold-enhancing plate need to be returned to their respective home positions provided outside the sheet conveying path so that the sheet bundle remaining in the sheet conveying path can be removed.
The inventors of the present invention have developed a sheet processing apparatus allowing a user to move the folding plate and the fold-enhancing roller pair manually via a drive transmission mechanism, by manually rotating an operation knob. With such a structure, a user can rotate the operation knob to move the folding plate and the fold-enhancing roller pair to their respective home positions, and remove the sheet bundle from the sheet conveying path, when any abnormality occurs.
Because the user manually moves the folding plate and the fold-enhancing roller pair, if a separate operation knob is provided to each of the folding plate and the fold-enhancing roller pair, the operations become cumbersome or take a time.
In consideration of the foregoing, there is a need to provide a sheet processing apparatus that can reduce cumbersomeness and operation time required for an operator to manually make an operation for moving an abutting member and a pressing unit, and to provide an image forming system including the sheet processing apparatus.